Cloud Access Security Broker (CASB): The Key to Controlling SaaS Risk in 2025

The shift to the cloud has revolutionized business operations — but also created new blind spots.

As companies adopt SaaS apps like Google Workspace, Microsoft 365, Salesforce, and Slack, they lose direct control over how data is stored, shared, and accessed.

That’s where a Cloud Access Security Broker (CASB) comes in.

In this article, we break down what CASBs are, why they’re critical in 2025, and which platforms are leading the way.

What Is a Cloud Access Security Broker (CASB)?

A CASB is a security solution that sits between users and cloud services, monitoring and enforcing policies for data security, compliance, and threat protection.

CASBs provide visibility, control, and protection over data stored and used in cloud applications — even those not sanctioned by IT (aka shadow IT).

Why CASBs Are Essential in 2025

• SaaS apps store massive amounts of sensitive business data

• Shadow IT usage is widespread and often unmonitored

• Compliance requirements demand visibility into cloud activity

• Data leakage, account takeovers, and insider threats are increasing

• Endpoint solutions don’t cover the cloud layer

A modern CASB empowers organizations to embrace SaaS without sacrificing security.

Core Functions of a CASB

1. Visibility

   • Discover all cloud apps in use (sanctioned and unsanctioned)

   • Monitor user activity across apps

   • Audit file sharing, logins, access attempts

2. Data Security

   • Prevent sensitive data exposure (DLP integration)

   • Classify and tag data in the cloud

   • Apply encryption and access controls

3. Threat Protection

   • Detect anomalous behavior

   • Identify compromised accounts

   • Block malware in cloud storage

4. Compliance Enforcement

   • Map activity to standards like HIPAA, GDPR, SOX

   • Generate audit logs and reports

   • Set granular access policies per user or device

Key CASB Use Cases

Top CASB Solutions in 2025

1. Microsoft Defender for Cloud Apps (formerly MCAS)

Microsoft’s CASB is deeply integrated into the Microsoft ecosystem.

• Best for: Organizations using Microsoft 365

• Features:

  • OAuth token control

  • App discovery & risk assessment

  • Real-time DLP in apps like OneDrive and Teams

  • Session control for risky access

  • Integration with Entra ID (Azure AD) and Intune

2. Netskope CASB

A leader in the SSE and cloud security space.

• Best for: Large organizations with multicloud SaaS use

• Features:

  • Real-time inline and API protection

  • Advanced DLP for documents and chat apps

  • SaaS threat intelligence

  • Integrated SWG and ZTNA

  • Controls for managed and unmanaged devices

3. McAfee MVISION Cloud (Trellix)

A mature CASB with robust policy control and threat detection.

• Best for: Enterprises with strict data governance needs

• Features:

  • Continuous compliance monitoring

  • User activity monitoring with risk scoring

  • Granular sharing controls

  • Broad SaaS app coverage including Box, Salesforce, Slack

4. Cisco Cloudlock

A cloud-native CASB designed for API-based protection.

• Best for: Simpler deployments with Google Workspace and Salesforce

• Features:

  • Agentless deployment

  • Identity behavior analytics

  • Granular policy configuration

  • Threat alerts and automation

5. Bitglass (Forcepoint)

An all-in-one SSE platform with CASB at its core.

• Best for: Businesses looking for full-stack cloud security

• Features:

  • Inline protection without agents

  • User & entity behavior analytics (UEBA)

  • Shadow IT visibility

  • Real-time data protection for SaaS and IaaS

CASB vs Other Cloud Security Tools

CASBs are purpose-built for securing cloud applications and user behavior — a critical layer in SaaS-dominated environments.

Challenges of CASB Adoption

• Shadow IT sprawl is hard to fully identify

• API-only CASBs may miss real-time traffic unless integrated with proxies

• Policy complexity can lead to overblocking or gaps

• User experience may suffer if controls aren’t fine-tuned

The key is to adopt a CASB that offers both visibility and control, without slowing down collaboration or access.